Method of treating mixtures containing alkali salts of certain metals



Dec. 4, H928.

G. E. DALBEY ET AL METHOD 0F TREATING MIXTURES CONTAINING ALKALI SALTS 0F CERTAIN METALS Filed Jan. 14, 1'92'7 @Slm Sm ,SSN @Ql Q wm Egg KIN

Patent Dec. 4, 1928.. I

vauf 'rri- GEORGE E. DALBEY, OF EAST BERLIN, lAND THOMAS P. HANFORD, -OF BERLIN, CON- NECTICUT, ASSIGNOBS T THE STANLEY CHEMICAL COMPANY, OF EAST BERLIN',I CONNECTICUT, A CORPORATION OF CONNECTICUT. ,l

METHOD OF TREATIN G MIXTUBES CONTAINING .L .a

I SLTS OF CERTAIN METALS.

Application l'ed January 14, 1927. Serial No. 161,283.

l This invention relates to a method of treating mixtures containing alkali salts orA certain metals.

The particular mixtures in view include sodium arsenate, sodium stannate, sodium antimonate, sodium plumbate, sodium plumbite,

sodium zincate and free uncombined caustic alkali. They may include other sodium com pounds of metals or of metal oxides and may l0 lack the free caustic alkali, or one or more of the salts mentioned. These mixtures may, of course, be derived from various sources. It is noted, however, that such a mixture results from carrying out the several methods set forth in three copendin of even date herewith, erial Nos. 161,235, 161,236, 161,237. A mixture of this class also results from carryin out the method set forth in our application ed May 4:, 1926, Serial 2o No. 106,726. s

It is an object of the invention to provide an economical method of treating such mixtures whereby valuable products may be reclaimed on a commercially practical scale.

26 With this obj ect in View the invention cons'ists in the method which is hereinafter described then more particularly pointed out in the claims.

A How-sheet of the process is shown in the m drawing. v

In carrying out the method of the invention, the mixture is placed in water in such proportion that the water is saturated with any free caustic alkali, usually caustic soda.

As this caustic soda is the most readily solu- 'ble' of the materials involved there is formed a water solution of caustic soda, leaving the other materials out of solution and in suspension.

,40 During this step the sodium antimonate `changes to sodium pyro antimonate in the presence of the water.

The water solution of caustic soda is then removed by any suitable mechanical means, and may be used in other chemical reactions,

e. in the renement of lead. he residuum is again placed in water sufficient to dissolve any sodium stannate, sodium zincate and sodium arsenate. While a small amountI of sodium plumbate and sodium plumbite may go into solution the major portion remains in suspension with the applications filedl sodium pyro'antimonate and any insoluble materials, including oxides.

This solution ofsalts is separated from the undissolved materials by any suitable mechanical means. Its further treatment is later referred to.

Referrin now to the further treatment of the undisso ved materials, this latter mixture of sodium plumbate, sodium pyro antimonate and anyl impurities is treated to obtain metallic lead and sodium pyro antimonate. To this end, it is allowed to react with metallic tin, and in carrying out the invention to what is now considered the best advantage, just enough tin is used to reduce the sodium plumbate and sodium plumbite. As a result, the tin is changed to sodium stannate and the sodium plumbate is reduced to metallic lead. During this reaction, with a proper amount Y of tin, the sodium plumbate and sodium plumbite are substantially entirely reduced to lead before any action takes place on the sodium pyroV antimonate. This reaction leaves sodium stannate in solution and out of solution a mixture of sodium pyro antimonate and metallic lead.

The sodium stannate solution is then sepv arated out by suitable mechanical means. Also the sodium /pyro antimonate andthe metallic lead are separated by mechanical means such as a tabling operation or by ordinary classifiers. The sodium pyro antimonate can be further treated by smelting or otherwise to obtain metallic antimony.

Referring back to the solution` of metal salts previousl treated to obtain stannic acid. While other products result the stannic acid is considered the mostI valuable commercially. To this end, the solution is treated with a suitable sul- 'phur compound, e. g. sodium sulphide, to cause precipitation of metal sulphides. As -a result of this step the zinc, lead and any otherI metals formmg insoluble compounds in alkaline solution are precipitated out as sulphides. These precipitated materialsare lremoved in any suitable manner, leaving a relatively pure solution of sodium stannate and sodium arsenate.

This latter solution is'suitablytreated with an alkali carbonate, e. g. sodium acid carbonate, to change the sodium stannate to removed, this solution is stannic-acid. This may be accomplished it desired by treating the solution With carbon dioxide which combines With the caustic soda to form the sodium carbonate.

The stannic acid is precipitated out and may be separated by mechanical means. The sodium arsenate left in solution may be treated to recover arsenic or discarded.

vWhat is claimed is:

l. The method of treating mixtures containing sodium-metallic salts to recover valuable products, Which comprises dissolving any caustic soda Whichy may be present in the mixture and separating it from the undissolved materials, dissolving the metal salts other than sodium plumbate and plumbite i and any sodium pyro antimonate that may be present due to the action of Water on sodium antimonate in the original mixture, separating such solution from the undissolved materials, treating the undissolved mixture of sodium plumbate and vplumbite and Sodium p ro antimonate to obtain metallic lead and so ium pyro antimonate, and treating sai solution of metal salts to obtain stannic acl 2. The method of treating mixtures containing sodium-metallic v salts to recover valuable products, which comprises removing, by dissolving in Water and mechanical separation of the solution, any caustic. soda which may be present and the metal sodium salts other than sodium plumbate or plumbite and any sodium pyro antimonate that may be formed by the action of Water on sodium antimonate in the mixture, and treating the undissolvedmixture of sodium plumbate or plumbite and sodium p ro antimonate to obtain metallic lead an sodium pyro antimonate.

3. The lmethod of treating mixtures containing sodium-metallic salts to recover valuable products, which comprises removing, by dissolving in Water and mechanical ornplumbite to metallic lead.

separation of the solutions, any caustic soda which may be present and the metal sodium salts other than sodium plumbate or plumbite and any sodium pyro antimonate that may be formed by the action of Water on sodium antimonate inthe mixtureyand treating the undissolved mixture of sodium plumbate or plumbite and sodium pyro antimonate with metallic tin to reduce the sodium plumbate 4. The method of ltreating mixtures con-- taining sodium-metallic salts to recover valuable products, which comprises removing, by dissolving in Water and mechanical separation of the solution, any caustic soda.

which may be present and the metal sodium salts other than sodium plumbate or plumbite and any sodium pyro antimonate that may be fornied by the action of water-on sodium antimonate in the mixture, and treating the undissolved mixture of sodium plumbatelor reeaeai by dissolving in Water and mechanical separation of the solution, any caustic soda Which may be present and the metal sodium salts other than sodium plumbate or plumbite and any sodium pyro antimonate which may be formed by the action of Water on sodium antimonate in the mixture, separating the soda solution from the solution .of salts, and treating the solution of salts to obtain stannic acid.

6. rllhe method of treating mixtures containing sodium-metallic salts, to recover valuable products, which comprises removing, by dissolving in Water and mechanical separation ofthe solutions, any caustic soda Which may be present and the metal sodium salts other than sodium plumbate or plumbite and any sodium pyro antimonate which may be formed by the action of Water on sodium antimonate in the mixture, separating the soda solution from the solution of salts, treating the solution of salts with a sulphur compound to precipitate sulphides of metals forming insoluble compounds in an alkali solution, removing such precipitated sulphides, and treating the remaining solution With an alkali carbonate to precipitate stannic acid.

7. The method of treating mixtures conm taining sodium-metallic salts, to recover valuable products, which comprises removing, by dissolving in Water land mechanical sepa` ration of the solutions, any caustic soda which may be present and the metal sodium salts other than ,sodium plumbate or plumbite and any sodium yro antimonate which may be formed by t e action of Water on sodium antimonate in the solution, 'separating the soda solution from the solution of salts, treating the solution of salts to obtain a relatively pure solution of sodium stannate'and sodium arsenate, and treating said last-named solution With an alkali acid carbonate or carbon dioxide to precipitate stannic acid.

8. The method of treating mixtures containing sodium-metallic salts and free caustic alkali to recover valuable products which comprises forming a Water solution of caustic alkali while maintaining substantially all the other products out of solution, and lseparating such Water solution from the mixture by mechanical -means.

9. The method of treating mixtures conf taining sodium-metallic salts and free caustic alkali to recover valuable products, which comprises forming a vvater solution of caustic alkali While maintaining substantially all the aceaeai other products out of solution, separating 30 suoli water solution from the mixture loy mechanical means, and treating the residuum to obtain metallic lead.

lln testimony whereof, We have hereunto .set our hands.,l

GEORGE E. DALBEY. THUMAS P. HARTFORD. 

